If you're feeling like you'd like to get out socialising again, or dating, then step 1 is to find yourself a good, reliable babysitter with affordable rates.
Maybe a friend who has older teenage daughters or a relative ?
Once you have the childminding aspect sorted, I'd start by going out with my friends again at first. It's amazing how many relationships started by my pals meeting a guy on our girls nights out.
If and when you felt ready to try 'dating' again, you could sign up to online dating, but think of it more like 'testing the waters'. Chat to lots of guys, weeding out the nasty, icky ones first. (i.e the ones who suddenly send you an unsolicited 'dick pic', or who ask sexual questions etc)
Eventually you'll get along with a guy and then you can move onto 1st date territory (where you'll again, weed out the icky, nasty ones). Just make sure you meet somewhere very public, never give out your phone number or address or even where you work. (I used to use a pay as you go phone for dating rather than give out my real mobile number)
Trust your instincts
Keep home/work/life details very vague