Det ser ud til, at mit skema er ændret, for forelæsningen begynder en time senere i dag.

Yes. Se ud til is a fixed expression meaning to seem or to look as if.

So:

• Det ser ud til, at ... = It looks/seems that ...

You should learn ser ud til as one chunk, because the meaning is not fully predictable from the individual words ser, ud, and til.

Here det is a dummy subject, like English it in It seems that ....

So:

• Det ser ud til, at ... = It seems that ...

You use det in many impersonal expressions in Danish. Der would not be natural here.

Because skema is a neuter noun:

• et skema = a schedule / timetable

With singular neuter nouns, my is mit:

• mit skema = my schedule

Compare:

• min for common-gender singular nouns
• mit for neuter singular nouns
• mine for plural nouns

Because at introduces a subordinate clause, and subordinate clauses in Danish normally do not use main-clause V2 word order.

So after at, the normal pattern is:

• subject + verb

That gives:

• at mit skema er ændret

not a reordered version with the verb earlier.

This is an important contrast in Danish:

• main clause: often V2 word order
• subordinate clause: more regular subject-before-verb order

Ændret is the past participle of ændre.

In mit skema er ændret, Danish is describing the schedule as being in a changed state. In English, this is often best translated as has been changed.

So although the Danish literally looks close to is changed, the natural English meaning is often:

• my schedule has been changed

If you wanted to emphasize the process even more explicitly in Danish, you could also say:

• mit skema er blevet ændret

But er ændret is very natural.

Here for means because / since. It is a conjunction giving a reason:

• ..., for forelæsningen begynder en time senere i dag
• ..., because the lecture starts an hour later today

This use of for is real Danish, but it can feel a bit more written or formal than fordi.

So this sentence could also be expressed with fordi, though the structure would then be slightly different in style.

Because Danish, like English, often uses the present tense for scheduled future events.

So:

• forelæsningen begynder en time senere i dag

means:

• the lecture starts an hour later today

This is completely normal. Danish does not need a special future form here.

Because forelæsningen is the definite form:

• en forelæsning = a lecture
• forelæsningen = the lecture

Danish usually puts the definite article at the end of the noun rather than using a separate word like English the.

Here it refers to a specific lecture that is understood from the context.

En time senere means an hour later.

• senere = later
• en time = an hour

This is a very normal Danish pattern for expressing a time difference:

• en dag senere = a day later
• to uger senere = two weeks later

So begynder en time senere means starts one hour later than expected / than usual.

The comma before for is straightforward: it separates clauses.

The comma before at depends on comma style. Many Danes use start comma, where a comma is placed before a subordinate clause. So:

• Det ser ud til, at mit skema er ændret ...

is correct in that system.

You may also see:

• Det ser ud til at mit skema er ændret ...

without the comma before at. That is also common in modern Danish.

So the comma before at is mostly a matter of comma convention, while the comma before for is more expected as clause separation.