La tapadera de vidrio está caliente, así que uso un trapo para cogerla.

Because in Spanish, definite articles like el / la / los / las are used more often than the is in English.

Here, la tapadera means the lid. The speaker is talking about a specific lid, not just any lid in general.

• La tapadera está caliente = The lid is hot
• Tapadera está caliente would sound incomplete or unnatural in normal Spanish.

Also, tapadera is feminine, so it takes la.

Yes. In many situations, tapa is more common than tapadera for lid.

• la tapa = lid, cover
• la tapadera = lid, cover, sometimes a bit more specific or descriptive

In everyday Spanish, especially in many contexts, tapa often sounds simpler and more natural. But tapadera is still a real and correct word.

So these are both possible:

• La tapa de vidrio está caliente
• La tapadera de vidrio está caliente

Both can be possible, but they are not always exactly the same.

• vidrio = glass as a material
• cristal = glass too, but often used for glass objects, panes, or finer glass

In a sentence like this, de vidrio clearly means made of glass.

So:

• tapadera de vidrio = glass lid

In Spain, you may also hear tapa de cristal in some contexts, especially for things like oven lids, table tops, windows, or more polished glass items. But de vidrio is perfectly correct.

Because caliente here describes a temporary state, not a permanent characteristic.

Spanish uses:

• estar for states or conditions
• ser for identity, classification, and more permanent qualities

A lid being hot is temporary, so:

• La tapadera está caliente = The lid is hot

If you said es caliente, that would sound wrong here, because the lid is not inherently hot all the time.

Así que means so, therefore, or so that’s why. It introduces a result.

• La tapadera de vidrio está caliente, así que uso un trapo...
• The glass lid is hot, so I use a cloth...

It is not the same as porque.

• porque = because, gives the reason
• así que = so, gives the result

Compare:

• Uso un trapo porque la tapadera está caliente.
  I use a cloth because the lid is hot.

• La tapadera está caliente, así que uso un trapo.
  The lid is hot, so I use a cloth.

Spanish often uses the simple present where English might use either I use or I’m using, depending on context.

• uso = I use / I am using

In a sentence like this, uso sounds natural and general: it describes what the speaker does in that situation.

Estoy usando is possible, but it emphasizes that the action is in progress right now. In many everyday sentences, Spanish prefers the simpler form.

So:

• uso un trapo = natural and normal
• estoy usando un trapo = possible, but more specifically I’m using a cloth right now

Yes, but the meaning changes slightly.

• un trapo = a rag, cloth
• un paño = a cloth, often a bit more neutral or tidy-sounding
• una toalla = a towel

In this sentence, un trapo suggests an ordinary cloth or rag used to protect your hand from the heat.

Depending on the situation, you might also hear:

• uso un paño para cogerla = I use a cloth to pick it up
• uso un agarrador = I use a pot holder
• uso un guante de cocina = I use an oven glove

So trapo is correct, but it has a slightly rougher, more everyday feel.

Because -la means it, and it refers back to la tapadera.

• coger = to take / to pick up / to grab
• cogerla = to take it / to pick it up

Since tapadera is feminine singular, the object pronoun is la.

So:

• para cogerla = in order to pick it up

Without la, the sentence would be less complete because it would not say what is being picked up.

In Spanish, object pronouns can be attached to an infinitive.

That is what happens here:

• coger + la = cogerla

This is very common after words like:

• para
• quiero
• voy a
• necesito

Examples:

• para cogerla = to pick it up
• quiero verla = I want to see her/it
• voy a hacerlo = I’m going to do it

You could also sometimes place the pronoun before a conjugated verb in other structures, but with a bare infinitive like this, attaching it is the normal form.

Yes. In Spain, coger is a very normal everyday verb meaning:

• to take
• to pick up
• to catch

So in Spain, cogerla here is completely natural.

However, this is important: in much of Latin America, coger can be vulgar or have a sexual meaning. Because of that, learners are often taught alternatives such as:

• agarrar
• tomar
• recoger (depending on context)

But since you are learning Spanish from Spain, coger is absolutely fine and very common.

Because de + material usually does not take an article when you are describing what something is made of.

• de vidrio = made of glass
• de metal = made of metal
• de madera = made of wood

So:

• tapadera de vidrio
• mesa de madera
• botella de plástico

If you said del vidrio, that would usually mean from the glass or of the glass, referring to a specific piece of glass, which is a different idea.

In this sentence, the best natural meaning is pick it up or take hold of it.

Because the lid is hot, the speaker uses a cloth in order to hold it safely.

So cogerla here suggests:

• taking hold of the lid
• lifting it
• picking it up

Depending on context, coger can mean slightly different things, but here it is about physically handling the lid.

Because así que introduces the consequence of the first idea, and Spanish normally separates that kind of clause with a comma.

• La tapadera de vidrio está caliente, así que uso un trapo...

This is similar to English:

• The lid is hot, so I use a cloth...

The comma helps show the pause between the cause and the result.