Optional Lesson 2: Bonus auxiliaries: 見る, とする, と思う, と決める
Many ordinary verbs have additional uses as "auxiliary" verbs, verbs attached to the end of the verb-sticky form or て form of another verb. Instead of meaning what they normally mean, they're used to express things that japanese doesn't have dedicated verbal conjugations for.
Most of these are very easy to pick up from reading, except for how complicated とする is. とする has enough to say about it that I consider it advanced grammar, which is the only reason it's buried away in this optional lesson rather than being put in the later course lesson on "aspect".
見る, in the construction てみる, as in 食べてみる, indicates that the action is "tried", or being done "to see what happens". This can overlap with the normal meaning of みる, but not always.
読んで見る I'll read it and see (what it's like).
食べてみる I'll try to eat it.
In the next three auxiliaries, the と is the embedded clause marker. This might help you understand how that use of と works.
とする has three main uses. The first means that someone supposes/assumes something, used with statements. Think of it like "pretend that/act as though". This is easiest to see as an invitation, but can be part of a longer sentence about someone else's presumptions too.
それが犬だとする Let's say that's the dog.
来たとする Assume it came.
The second is として, with a general vague "operating as X" meaning. This is directly related to the first use, think of it like "thinking of Y as an X", but it doesn't work the same way psychologically.
研究者として As a researcher
The third use means that something undergoes an "experiential" state, basically used with "mimetic" words like つるつる "slick".
つるっとする It goes "slurp"
と思う has two main uses.
Normally, と思う means that the speaker thinks something.
来たと思った I thought that it came.
When と思う is used with a volitional phrase, it can mean the speaker thinks that they should do something.
食べようと思う I think I should eat.
When the speaker wants to talk about someone else supposing that they should do something, they have to use the ている form of と思う.
彼は勉強しようと思っている He thinks he might as well study.