Hi Nia!
Recessive is when a specific trait is not expressed within the phenotype. For example, Tall is expressed but short gene isn't. Therefore the short gene is the recessive.
Autosomal recessive is one of the mode of inheritance and is not sex linked (X-linked). This means that the characteristic inherited from the parent(s) can be any of the 22 chromosomes (excluded the 23rd as it is X-linked).
Now, this mode of inheritance means that the recessive trait is PASS down and most likely expressed in the offspring if the parent(s) (dad and/or mum) are AFFECTED.
It can affect both sexes and it may skip generations.
For example, Generation 1 Dad (AA) and Mum (aa) has any evidence of the recessive trait being expressed in the Genotype . Generation 2 (son (aa) has recessive expressed phenotypic and daughter(Aa) will have recessive expressed in the genotype. Generation 3 (son (aa) marries affected Woman (aa)) therefore their son(s) and/or daughter(s) are bound to obtain the recessive trait unless a new mutation occurs.
An example of a genetic disease that occurs in an autosomal manner - familial hypercholesterolemia.
(THAT WAS A VERY SIMPLE, NOT SCIENTIFIC EXAMPLE. Take it with a grain of salt... just understand it so you get the gist of it).
I hope I explain it right haha!
If you are confused about something, ASK! or if anyone notices that I may have explained something wrong. Be free to correct me!!
Nonetheless, I hope this helps