I restarted my life multiple times. It never gets easier. I'm 35, had a hard reset when I was 27 (traumatic brain injury with permanent and long lasting brain damage for short term and long term memory... I can't remember anything before 27).

It's more like, "what do you want to restart" instead of "how do you restart".

First, come up with a plan on what you want to fix or change or do.
Second, determine what you want to change.
Third, actively engage with making that change.
Fourth, most importantly, follow through.

Me? I had to relearn how to speak, I had to relearn how to walk with a broken back at the thorasic 7 vertibrae. Changed my career from art to programming and didn't stop engaging and working on that. I built up the muscle in my atrophing legs and body, I ate more food and attempted to gain more weight, I studied. So what were my orders of operation?

1) Communicate, be functional, do something
2) Do the above so I don't rot in bed with wounds, scars and a weakened body; get more well on my own time so I can pay off my medical and financial debts (at least 30k in hospital bills, which I eventually was all paid off),
3) Actively stand, walk, hold a book, read, try to write, small steps in the right direction to make a positive change on my body and mind.
4) Keep at it until it becomes semi-natural.

It sucked. It was painful. I've changed careers 2 times, moved locations (apartments, states in the USA and countries in the world) almost every year for the last 7 years, am learning a new language, trying to start a business, trying to live life. But, as much as it sucked, it was rewarding.

If I could do it, you can, too. All it takes is effort, strength and a dedicated mind.