"Mathematics is the first subject on our schedule today."
Translation:Matematika adalah pelajaran pertama di jadwal kami hari ini.
Maybe it'll help if you read the grammar topics.
Here is a 'sticky' topic with all the grammar topics that were posted in the previous months:
Here are the relevant topics for your question :
Ada, Tips & notes, Addendum.
Adalah, Tips & notes, Addendum.