When i teach Japanese grammar, verb conjugation is a big ploblem.
In best seller lesson book in Thailand “Minna no nihongo“, that teach ます(masu) form first.
Actually, almost of all books for begineers uses “ます form” .
so,  Verb conjugation is hidden.
Books for beginners teaches like this.
たべます　tabemasu (eat, will eat)
たべました tabemasita (ate)
たべません tabemasen (don’t eat, won’t eat’)
たべませんでした tabemasendesita(didn’t eat)
You can make them mechanical because only one rule is applied for any cases.
But you will face verb conjugation in books for advanced students.
In “minna no nihongo”Vol2 teaches Verb conjugationfrom lesson14.

please remember some points.

Verbs in Japanese
A>there are 3 groups.
B>they are called group1,group2,group3 here.
C>verbs in group2 and group3 are conjugated mechanicaly.
D>conjugation of verbs in group1 is complexed.
E>Only 2 words are in group3.they are  simasu(do) kimasu(come).
F>when you learn new verb, you should remember its group.it will help you conjugate the verb.