Calculations for my Portfolio

First excuse my maths and limited finance knowledge.

I am testing investing in crypto and trying to calculate my ROIs, Profit/Loss etc and getting stuck a bit and was wondering if anyone can help!

First example
Lets say i buy

10 BTC for 100 USD/ coin on 1st of January making the total investment
of 1000 USD

i know we all wish

Lets say the Current Value for BTC is 300 USD/coin

My Profit/Loss will be 2000USD which is 3000 (current value) - 1000 (initial investment)

My ROI is 2000/1000 which is 2%

I think so far i am on the right track!

Now my first question is
Lets say i buy

10 BTC for 250 USD / coin on 5th of Jan

How do i factor in

1. My Profit Loss
2. My ROI

My Second question is
Lets say i SELL

5 BTC for 150 USD / coin on 10th of Jan

Again how do i factor in my

1. My Profit Loss
2. My ROI

I think what i am missing is how i calculate my Total Invested amount.

And my third question is how do i calculate my Daily ROI after buying and selling coins over time?

I appreciate that this is way too much to ask, so perhaps google terms to search for will suffice. As i think i am missed the correct terms to use in my searches.

Thanks