Возьмите прихватку: противень ещё горячий.

Возьмите is the imperative form used for:

• more than one person: Take a potholder
• one person politely/formally: Please take a potholder

Возьми is the singular informal version, used with one person you address as ты.

So:

• Возьми прихватку = take a potholder (to one friend, child, etc.)
• Возьмите прихватку = take a potholder (to several people, or politely to one person)

Because it is the direct object of the verb возьмите.

The basic form is прихватка. Since it is a feminine noun ending in -а, its accusative singular changes to -у:

• nominative: прихватка
• accusative: прихватку

So Возьмите прихватку literally means Take a potholder / oven mitt.

Прихватка is a kitchen item used to hold hot cookware. In English, depending on context, it can be:

• potholder
• oven mitt
• hot pad

Very often it suggests a small cloth potholder, but in everyday translation oven mitt or potholder both work depending on the situation.

Противень means baking tray, oven tray, or sheet pan.

It is a masculine noun. In this sentence it is in the nominative, because it is the subject of горячий:

• противень ещё горячий = the tray is still hot

In this sentence, ещё means still, not more.

So:

• противень ещё горячий = the tray is still hot

This is a very common use of ещё with adjectives and states:

• Он ещё занят. = He is still busy.
• Суп ещё тёплый. = The soup is still warm.

So here ещё tells you that the tray has not cooled down yet.

Горячий is the full adjective form, agreeing with противень, which is masculine singular.

• противень = masculine singular
• therefore горячий = masculine singular adjective

Why not the others?

• горячо is usually an adverb or a neuter predicative form, so it would not match противень
• горяч is the short-form adjective; it exists, but in modern everyday speech противень ещё горячий sounds more natural and common

So the sentence uses the standard everyday pattern: noun + ещё + full adjective

Both can mean take, but there is an aspect difference.

• возьмите comes from взять (perfective)
• берите comes from брать (imperfective)

In this sentence, возьмите is natural because it means take one now / do it once. It focuses on the completed action.

Берите can also be used, but it often sounds more like:

• go ahead and take
• take one
• a more general or less bounded action

Here, because the speaker is warning someone about a hot tray, Возьмите прихватку is the most natural choice.

The colon shows that the second part explains the first part.

• Возьмите прихватку = take a potholder
• противень ещё горячий = the tray is still hot

So the structure is basically:

Take a potholder: the tray is still hot.

In English, a colon works similarly here, though a dash or separate sentence would also be possible. In Russian, the colon neatly marks reason/explanation.

The main stresses are:

• возьмИте
• прихвАтку
• протИвень
• ещё
• горЯчий

A rough pronunciation guide:

• возьмИте ≈ vaz-MEE-tye
• прихвАтку ≈ pree-KHVAHT-koo
• протИвень ≈ pra-TEE-vyenʹ
• ещё ≈ yeesh-CHO
• горЯчий ≈ ga-RYA-chee

A useful thing to remember is that ё is always stressed.

The literal structure is exactly that:

Take a potholder: the tray is still hot.

But in natural English, people often say:

• Use an oven mitt — the tray is still hot.
• Take a potholder; the baking tray is still hot.
• Use a potholder, the tray is still hot.

So the Russian sentence is straightforward, but the most natural English wording may vary depending on context and the kind of kitchen item you want to name.