Luen lukujärjestyksen tarkasti suunnitellakseni koeviikon niin, että minulle jää aikaa levätäkin.

In Finnish, the verb ending already shows the subject.

• luen = I read
• the ending -n marks first person singular

So minä is usually omitted unless you want emphasis or contrast.

• Luen = normal, neutral
• Minä luen = I read, maybe contrasting with someone else

Lukujärjestys means a timetable, class schedule, or school schedule.

It is a compound noun:

• luku
• järjestys = order

But as a whole, lukujärjestys is a fixed everyday word for a school timetable. You do not need to think of it literally as reading order in normal use.

Here lukujärjestyksen is the object of luen.

In Finnish, a singular total object in an affirmative sentence often looks like the genitive form. That is why you get -n-type object forms.

So:

• luen lukujärjestyksen = I read the timetable, as a whole / thoroughly

Also, nouns ending in -s often change their stem in these forms:

• lukujärjestys → lukujärjestyksen

That -ksen pattern is normal for many nouns of this type.

For the same basic reason: koeviikon is the object of suunnitella.

• suunnitella koeviikko = to plan the exam week

In this sentence, the object is treated as a whole, so Finnish uses the singular total object form:

• koeviikon

This is not possession here. It does not mean of the exam week. It is the object form.

Tarkasti is an adverb meaning carefully, closely, or thoroughly.

It modifies luen:

• Luen lukujärjestyksen tarkasti = I read the timetable carefully

It comes from the adjective tarkka = careful, precise.

Suunnitellakseni is a purpose form meaning in order for me to plan or more naturally in order to plan.

It is built from:

• suunnitella = to plan
• -kse- = a purpose marker
• -ni = my, but here it marks that I am the doer

So:

• suunnitellakseni = in order for me to plan

This form is often called the first infinitive translative or the long infinitive form with a possessive suffix.

Yes. It is a normal Finnish structure, especially in written or slightly more compact style.

A more explicit alternative would be:

• Luen lukujärjestyksen tarkasti, jotta voin suunnitella koeviikon...
• I read the timetable carefully so that I can plan the exam week...

The version with suunnitellakseni is more condensed. It is very useful to recognize, because Finnish uses it quite a lot in formal and standard written language.

Here niin, että means so that.

It introduces the result or intended outcome of the planning:

• suunnitellakseni koeviikon niin, että...
• to plan the exam week so that...

The clause after että explains what the desired result is:

• minulle jää aikaa levätäkin

Also, the comma is normal in Finnish before a subordinate clause introduced by että.

Minulle is the allative form of minä, and here it means for me or to me.

Finnish often uses this kind of structure with jäädä when something is left or remains for someone:

• minulle jää aikaa = time remains for me
• natural English: I have time left

So the Finnish structure is more literally:

• for me remains time

Even though English uses I have, Finnish often uses jäädä plus a case form like minulle.

Aikaa is partitive.

That is natural here because it means some time or enough time, not one clearly bounded, specific unit of time.

So:

• jää aikaa = there is time left / some time remains

This kind of partitive is very common with uncountable or indefinite amounts.

If you used aika, it would sound more definite and would not fit this structure nearly as naturally.

The basic infinitive is levätä = to rest.

After aikaa, Finnish uses an infinitive like English time to rest:

• aikaa levätä = time to rest

The clitic -kin adds the idea of also, too, or sometimes even.

So:

• levätäkin = to rest too / to rest as well

This suggests that rest is an additional important thing, not just studying and planning. A natural nuance is:

• so that I’ll still have time to rest too

Without -kin, the sentence would still be correct, but it would lose that extra sense of also/as well.