Need advice to practice safe sex

Hi everyone,

[M25] here. So, recently I have started exploring the online dating scene (hinge, bumble etc) and now I am facing a dilemma about safe sex.

For eg. A few of my dates offered (some subtly, some quite direct) to make out or have sex. But I get too freaked out over the thought of catching STDs. I know we can use a condom and stuff, but I read somewhere the some STDs can spread through, oral sex, kissing and even skin to skin contact.
I am talking to this really hot girl, and she has dropped some hints to have sex. Now, I REALLY want to get down with her, but again I am really afraid of the STDs. So, I just wanted to ask some of the experienced guys/gals here some questions (I will break down in points so that I can cover my doubts and it's easy to read)-

  1. A very simple solution can be to only have sex with girls you really know (like school/office/clg friends) but I dont really have much friends I am frank with. So, what points to keep in mind before kissing or having sex with someone you have met randomly with? (like on a dating app, insta or randomly in real life and exchanged social media)
  2. One can always have penetrative sex with condom (I know its still not 100% safe) but what about other stuff like kissing and oral sex? How risky is this stuff? And how can I do it safely?
  3. How do you make sure your partner is safe? I mean you can ask them but obviously you never know if they are telling the truth right? What if I Have sex and then find out they gave me some STD?
  4. If I want to experience unprotected sex. What things do I have to keep in mind?
  5. What STDs are very common and are permanently treatable? What STDs are not treatable like (HIV and herpes etc)? How common are both?
  6. Have you ever contracted an STD? How was your experience?
  7. Have you ever had an STD and lied to your partners about it while having sex?
  8. One of my friends have practiced unprotected sex with 2-3 girls. He told me generally STDs are present in people who have excessive unvetted partners and its not very common in general decent crowd. Is it true?
  9. What steps do you take to protect yourself?
  10. Am I overthinking?!

(Please: Serious replies only)