they look fancier then females. they want to look good for them. fish, in general, are hard to tell the gender. guppies are among the easier ones to do so though.
Guppies are amazing starter fish as they are very adaptable. you don't need a big tank I would recommend a 20 gal for breading. and if serious breeder (2) 20 gal tanks. but all you really need is a 10 gal if just wanting them as pets and nothing more.
They like any other fish require
1 heater
1 filtration system
1 fish tank
and some small rocks for there environment
people will often ask what are your fish parameters. for this, you can get test stips they run under 5.00. The neat thing about guppies is your water doest have to be perfect. just close. and people on here are super helpful! if u run into issues.
mine just had babies ^-^ and im no expert
best of luck cheers