A picture is worth a thousand words, but here goes...
Let's take our old pal propene, the smallest non symmetrical double bond alkene. We have a secondary carbon and a primary carbon with a double bond, so we have a Markovnikov and non Markovnikov carbon in the double bond (respectively). We also have a lonely methyl danging off taking no part of the double bond.
You treat the double bond as the Nucleophile, the electrons in the double bond are like a hidden lone pair (like undescended testicles). They act as the aggressors, to attack the electrophile or H+ from acidic water (H3O+). The double bond swings out and grabs off H+ from H3O+, creating a bond on the primary carbon, a plus charge on the secondary carbon, like pulling an arm off a fly the carbon lost a bond and has a plus charge.
Now the secondary carbon can take a new bond, specifically, from H2O. H2O is now the nucleophile for the second step, which attacks the plus charged carbon (carbocation), thus forming a bond at the Markovnikov position with water. You still have both Hyrogens attached to the water so you gotta "mop up" the last step, have another water rip off the extra H+ (proton),