PostgreSQL with inner join and multi select

Question

I'm trying to do an inner join from my main table and need to append a field in a second table. i'm completly new to SQL statments and have no idea how to write this out. i made a picture how the inner join works through 2 steps.

I wrote this untill now. Both work for themself, but no idea how to get them together.

Select *from Tabel1, Tabel2 where Tabel1.id = Tabel2.parent_id 
Select t2.field2 from Auftrag t1 inner join Tabel1 t2 On t1.id = t2.field1