There are 3 groups. the Ist the IInd and the IIIrd (Sherlock).
Ist group verbs have an "i" syllable (い, き, に, ひ, み, り, etc.) before the "ma" (ま) in the "masu" (ます) form. For exemple mochimasu (も
ちます) which means "to carry" is a Ist group verb : I bolded the "i" syllable before the masu form.
IInd group verbs have an "e" syllable before the "ma" in the "masu" form, but it might sometimes be an "i" syllable aswell (
みます - mimasu (which means to look at) is a IInd group verb. But た
べます (tabemasu = to eat) is a IInd group verb (I bolded the "e" syllable)
Then, the IIIrd group verbs are the verbs ending by "shimasu" (します) which are describing an action, and the verb "kimasu" (きます) which means "to come". But there are some exceptions iirc, for example "hanashimasu" (はなします) which means "to speak" is in the first group, not in the IIIrd.
Once you know this, there are some rules to know to "conjugate" your verb. To conjugate a verb by himself is quite easy, you always have to add the same thing at the end.
The hardest part imo, is when you had to add forms to you verb in order to express something (for example : to say you have to do something you'll have to change the end of your verb etc..), and there are several forms to know.
I'm sorry if I made no sense, a japanese guy/girl could be way more helpfull than I've been.
And hopefully I didnt say anything wrong
