How do i get started to plan for investment and retirement at age 35?

You need to ensure you have insurance and amount set aside for emergence first b4 talking about investment!

For $2k income you can do that if you can lock in about $300k into your CPF life at 55 years old. That can be achieved,

If plan retire before that. Min.15 years is achievable. DCA $2k per month (bare minimum) into S&P ETF. When you ready to retire re-allocate to dividend stock with min. 4 to 5% p.a. (local bank stocks)

Alternatively, renting rooms will also provide monthly income. At least 3 bedroom. 2 can rent 1 you stay yourself. At least can get $1k+