Guys,I need to gain weight...

I'm 168cm and 55kg.BMI says I'm good.But I look very thin physically.

I know calorie intake>>calorie burned to increase weight.Googled some tips but the food regime they recommend is quite impossible for me.

Have to eat every 3 hours, do own shopping and cooking and it's not cheap to buy the ingredients.

Any better ways?
My lifestyle is quite active. I walk and jump alot.Maybe I should reduce these?

Thanks