Für den Tee nehme ich einen Teelöffel Zucker, aber für den Salat nur einen Esslöffel Öl.

This is normal German main-clause word order.

In a German main clause, the finite verb must be in second position. If you put Für den Tee first for emphasis, the verb nehme has to come next:

• Für den Tee nehme ich ...

If you started with Ich, that would also be correct:

• Ich nehme für den Tee einen Teelöffel Zucker ...

Starting with Für den Tee highlights the contrast with für den Salat later in the sentence.

Because für always takes the accusative case.

Both Tee and Salat are masculine nouns:

• nominative: der Tee, der Salat
• accusative: den Tee, den Salat

So after für, you must say:

• für den Tee
• für den Salat

Because Teelöffel and Esslöffel are masculine nouns, and here they are in the accusative singular as objects of nehme.

• nominative: ein Teelöffel, ein Esslöffel
• accusative: einen Teelöffel, einen Esslöffel

So:

• Ich nehme einen Teelöffel Zucker
• Ich nehme einen Esslöffel Öl

Because Tee and Salat are part of the phrase für den ..., where German uses a normal article, while Zucker and Öl are being used as uncountable substances.

In this sentence:

• für den Tee / für den Salat = for the tea / for the salad
• Zucker / Öl = sugar / oil as material, not as a counted item

This is very common in German with ingredients:

• ein Glas Wasser
• eine Tasse Kaffee
• ein Löffel Zucker
• ein bisschen Öl

The amount is already expressed by einen Teelöffel or einen Esslöffel, so German usually leaves Zucker and Öl without an article.

German usually does not use a separate word like of in this kind of measure expression.

English:

• a teaspoon of sugar
• a tablespoon of oil

German:

• ein Teelöffel Zucker
• ein Esslöffel Öl

This pattern is extremely common. Other examples:

• ein Glas Wasser
• eine Flasche Milch
• ein Kilo Äpfel

So einen Teelöffel Zucker is the normal German structure.

Yes, nehmen basically means to take, but in contexts like cooking, recipes, ingredients, or amounts, it often means to use or to take/use a certain amount.

So here:

• Ich nehme einen Teelöffel Zucker
  means something like
• I use one teaspoon of sugar

This is very natural German.

Because nur usually goes near the part it is limiting.

Here, nur limits the amount:

• nur einen Esslöffel Öl = only one tablespoon of oil

So the idea is: for the salad, the amount is small — just one tablespoon.

If the full second clause were written out, it would be:

• ... aber für den Salat nehme ich nur einen Esslöffel Öl.

It can be repeated, but German often leaves out repeated words when the meaning is obvious.

Full version:

• Für den Tee nehme ich einen Teelöffel Zucker, aber für den Salat nehme ich nur einen Esslöffel Öl.

Shorter version:

• Für den Tee nehme ich einen Teelöffel Zucker, aber für den Salat nur einen Esslöffel Öl.

This is a normal kind of ellipsis. The missing nehme ich is understood from the first part.

Für focuses on purpose or intended use:

• für den Tee = for the tea
• für den Salat = for the salad

That works well because the sentence is comparing how much of something is used for one thing versus another.

If you said in den Tee, that would focus more directly on putting the sugar into the tea. That can also be possible in other contexts, but für is a natural choice here because the sentence is about comparing uses.

They are compound nouns:

• der Teelöffel = teaspoon
• der Esslöffel = tablespoon

They are built from:

• Tee
  • Löffel
• Ess-
  • Löffel

Esslöffel is the standard word for tablespoon. Both nouns are masculine:

• der Teelöffel
• der Esslöffel

That is why the sentence has einen with both of them in the accusative.

Because aber is a coordinating conjunction, and in German it is normally preceded by a comma when it connects two main-clause parts.

So this is standard punctuation:

• ..., aber ...

This is one of the common German comma patterns learners see early on.

Because all German nouns are capitalized.

So in this sentence, these are capitalized because they are nouns:

• Tee
• Teelöffel
• Zucker
• Salat
• Esslöffel
• Öl

This is a basic rule of German spelling and one of the easiest ways to spot nouns in a sentence.