"Here is my phone."
Translation:Вот мой телефон.
The word for "my" changes to match the gender and number of the noun it's describing. In the nominative (subject) case, the different forms are: мой (for masculine nouns); моя (feminine); моё (neuter); and мои (plural). There are other forms for the other cases, but you'll pick those up as you go through the course.
Nouns ending in "а" or "я" are feminine; nouns ending in "о" or "е" neuter; those ending in a consonant are masculine. (There are exceptions, such as "папа", which is masculine for obvious reasons.)
Nouns ending in a soft sign "ь" can be either masculine or feminine. Mostly you just have to learn these individually.
Where we expected to learn the differences of word forms yet? I believe my keyboard doesn't know the 'и' with the accent mark and I was incorrect for using it without the mark. It seems we've skipped way ahead, or did I miss something? Is there an easy and quick way to learn it?