You first need to know how the genders work. There are two genders, but there used to be three. The past three were masculine, feminine and 'neuter' (no gender (same system as current day Norwegian)), but it was changed to mix the masculine and feminine together into 'common gender'.
Today, Swedish just has common gender and neuter.
Common gender and neuter have different singular and plural. Also, singular and plural have definite and indefinite (indefinite is 'a car' because it could be any car, but definite is 'the car' because it would be only used in a situation where there can only a specific car. )
For indefinite common gender in singular, as in 'a car', you put 'en' before the word. So 'a car' is 'en bil.'
For indefinite neuter, as in 'a house', you would put 'ett' before the word. Notice how 'ett' means 'one' :) This means 'a house' is 'ett hus' in Swedish
Definite is basically the same. Just put the indefinite bit onto the end of the word - 'bilen', 'huset' (drop the second 't' on 'ett')
Plural is identical for both genders, for the most part. For indefinite plural, put 'er' on the end of the word. Note that if the word ends in a vowel, you just add an 'r', so 'a woman - en kvinna' is 'women - kvinnor' (sometimes the vowel changes, but just stick with 'er' for now and let people correct you c: )
Note that if it is a neuter word with only one syllable, you don't do anything to it. Just take the 'ett' from the start and it's fine. :)
The definite versions are pretty much the same, too!
Just ass 'na' after the indefinite plural one - 'kvinnorna'
For neuter words with only one syllable, like hus, you will add 'en' to the end. You don't even need to learn anything new :D
I hope this was somewhat conclusive - if you need any more help, you can add me :)
To find the gender of the word, just ask "Vad kön är det?" - "What sex is it?" ot stick it it google translate :P