I’m wanting to bulk up in size but not sure how : GYM

I’m 6ft 1, 11st 6lb… people say I look lanky and my body shape is just flat.

I’m looking to gain some size but I’m not sure the best way to go about this. I eat pretty regular with lots of carbs and protein such as: chicken and rice, pasta dishes, chicken and chips etc. But I don’t seem to put on any size.

Is there exercises I should be doing alongside this to gain the size? Should I been taking protein shakes or supplements?

I’m a novice so excuse my lack of knowledge.

Thanks.