zyagaimo wo yawarakaku nita ato, sore wo pan de tutunde tabete mita.

Not in normal Japanese writing. Standard Japanese is usually written without spaces:

じゃがいもをやわらかく煮たあと、それをパンで包んで食べてみた。

The spaces here are just for learners, to make the parts easier to see.

Because やわらかい is an -i adjective, and when an -i adjective modifies a verb, it usually changes to -く.

• やわらかい じゃがいも = a soft potato
• じゃがいもを やわらかく 煮る = cook the potato so that it becomes soft

So やわらかく is the adverbial form: softly / until soft / in a soft state.

Because 煮た is part of 煮たあと, which means after cooking/boiling.

In Japanese, the plain past form of a verb can be used before a noun or a grammar word like あと to show that one action is completed before another.

So:

• 煮る = to boil / simmer / cook
• 煮た = boiled / cooked
• 煮たあと = after boiling / after cooking

This does not mean the sentence is ending there. It just marks that this action happened first.

Here あと means after.

In this pattern:

• Vたあと = after doing V

So:

• 煮たあと = after cooking it

あとで is related, but it is often used more like later or after that as an adverb.
You can also say 煮たあとで, which is very similar here.

In this sentence, 煮たあと is a compact way to make a time phrase: after boiling it until soft.

それ refers to the じゃがいも that was just mentioned.

So the flow is:

1. cook the potato until soft
2. after that, wrap it
3. try eating it

Japanese often uses それ to refer back to something already mentioned, like it or that in English.

It could be omitted if the meaning is already clear from context. Japanese often leaves out pronouns.

For example, a speaker might also say something like:

じゃがいもをやわらかく煮たあと、パンで包んで食べてみた。

That would still be understandable.

Including それ makes the object more explicit: that / it.

Because there are two different places where a direct object is being marked.

• じゃがいもを goes with 煮た
  → cooked the potato
• それを goes with 包んで and also naturally carries into 食べてみた
  → wrapped it and tried eating it

So each を belongs to a different part of the sentence.

Here で marks the means/material used to do something.

So パンで包む means wrap it using bread or wrap it in bread.

This is similar to:

• 紙で包む = wrap in paper
• 布で包む = wrap in cloth

If you changed the particle, the meaning would change:

• パンを包む = wrap the bread
• パンに包む is not the natural choice here

So で is showing what is used as the wrapping material.

The -te form is often used to connect actions.

Here it links:

1. パンで包んで = wrap it in bread
2. 食べてみた = tried eating it

So the sentence gives a sequence of actions:

• cooked it until soft,
• then wrapped it in bread,
• then tried eating it

This is a very common use of the -te form in Japanese.

That is normal in Japanese clause chaining.

Earlier actions are often connected in forms like -て or before words like あと, and the final verb carries the main tense of the sentence.

So in:

• 包んで
• 食べてみた

the final みた gives the past sense to the overall sequence.

No. 〜てみる is a grammar pattern meaning to try doing something.

So:

• 食べる = eat
• 食べてみる = try eating
• 食べてみた = tried eating

It often has the nuance of doing something as an experiment or to see what it is like.

So this sentence suggests something like: the speaker wrapped it in bread and tried eating it to see how it was.

Because Japanese often omits the subject when it is already understood from context.

English usually needs a subject, but Japanese often does not. So the sentence can simply describe the actions without saying who did them.

Depending on context, the subject could be:

• I
• he
• she
• we

and so on.

By itself, it can be either singular or plural, depending on context.

Japanese nouns usually do not have separate singular/plural forms the way English does. So:

• じゃがいも can mean a potato
• or potatoes

The translation depends on the situation, not on the noun form itself.