Podemos poner la cómoda al lado de la cama, con tal de que la puerta siga abriéndose bien.

Because cómoda can be either:

• an adjective: cómoda = comfortable (feminine)
• a noun: la cómoda = chest of drawers / dresser

Here, the article la shows it is a noun. So la cómoda is the furniture item.

This is a useful false friend for English speakers, because it looks a lot like comfortable, but in this sentence it definitely means the furniture.

Poder + infinitive is the normal way to say can / are able to do something.

So:

• Podemos poner... = We can put...
• Ponemos... = We put... / We are putting...

If the idea is possibility or permission, Spanish usually uses poder.

Al lado de is a fixed expression meaning next to / beside / by the side of.

So:

• al lado de la cama = next to the bed
• al lado del armario = next to the wardrobe

It is best learned as one chunk: al lado de.

Because a + el contracts to al in Spanish.

So:

• a + el lado → al lado

This happens very regularly:

• Voy al supermercado.
• Está al lado de la cama.

The only very common exception is when el is part of a proper name, such as a El Escorial.

Con tal de que means provided that, as long as, or on condition that.

It introduces a condition that must be met.

In this sentence, the idea is:

We can put the dresser next to the bed, provided that the door still opens properly.

It is a common and natural expression, not especially formal.

Because con tal de que is one of the expressions that normally triggers the subjunctive.

Why? Because it introduces a condition, requirement, or non-factual situation rather than a simple statement of fact.

So:

• con tal de que la puerta siga... = provided that the door continues...

Here siga is the present subjunctive of seguir.

On its own, seguir often does mean to follow:

• Sigo al profesor. = I follow the teacher.

But seguir + gerund means to keep doing or to continue doing:

• seguir hablando = to keep talking
• seguir trabajando = to continue working
• seguir abriéndose = to continue opening

So in this sentence, siga means continues / keeps.

After seguir, Spanish normally uses a gerund to express continuing an action.

So the pattern is:

• seguir + gerund

Examples:

• sigue lloviendo = it keeps raining
• sigue funcionando = it keeps working
• siga abriéndose = it continues opening

So:

• siga abriéndose = correct
• siga abrirse = not correct here

It is abriéndose because the basic verb here is abrirse, not just abrir.

Because with things like doors, windows, and shops, Spanish very often uses the pronominal form abrirse to mean to open.

So:

• La puerta se abre bien. = The door opens well.
• La ventana no se abre. = The window won’t open.

This se does not have to be translated literally as it opens itself. In English we simply say the door opens.

Without se, abrir usually needs someone doing the action to something:

• Abrimos la puerta. = We open the door.

Yes. La puerta siga abriéndose bien and la puerta se siga abriendo bien are both correct.

With a conjugated verb plus a gerund, the pronoun can often go in either place:

• before the conjugated verb: se siga abriendo
• attached to the gerund: siga abriéndose

They mean the same thing. The version in your sentence is very natural.

Because when a pronoun is attached to a gerund, Spanish often adds a written accent to keep the original stress.

Compare:

• abriendo
• abriéndose

The accent shows that the stress stays where it should.

You see the same thing in:

• diciendo → diciéndose
• poniendo → poniéndose

Here bien means something like properly, smoothly, or without difficulty.

So la puerta siga abriéndose bien does not just mean that the door still opens at all. It means the door should still open normally, without hitting the furniture or getting blocked.

So a natural English sense is:

• the door still opens properly
• the door still opens fine
• the door can still open without problems

The comma separates the main idea from the condition:

• Podemos poner la cómoda al lado de la cama
• con tal de que la puerta siga abriéndose bien

This kind of comma is very natural in Spanish, especially when the second part adds a condition or limitation. In a short sentence, punctuation can vary a little, but the comma here is completely normal and helps the sentence read clearly.