This rhythm is very complex for a beginner.
Obvious you can’t read sheet music and have no idea of rhythm. Tutorials like this are useful to motivate you to play piano but they are a bad help to develope the lacking rhythm feeling and freedom of singing and bring both together. As you are able to play the song without singing you’d better choose now another video and try to sing together with the singer or accompany the song.
If this don’t work then you have to analyze the rhythm:
Start with intro! You can hear the chords
You have first to write the lyrics line by line
like a poem that you have an overview of the verses, refrain and the bridge.
Then make a sign or an accent above the syllable where you have to play a chord, and write dots where you can hear only single notes.
Look at the video you can see the note names (when the letters are in a row) up and down and the chords, e.g. in the bridge or refrain. The chords are triades and notated vertically.
You have to copy them on a sheet respective to the lines of the lyrics, the phrases and the verses.
Try to play them synchronized looking at the lyrics.
The best will be you prepare the 4 x 2 bars for the intro:
Count the 8th notes in each measure:
The bold beats are marking the place (time) when the chords have to be played:
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
Tap with your feet the pulse 1-2-3-4 (the quarters)
and count in double speed the 8th notes 12345678.
Play the chords of the intro counting this rhythm.
When you are able to count emphazing 1,4,7 then you have got the rhythm and may probably be able to sing later to your own accompaniment.
May be after all this practise you will be able to play this one song you love so much.
You see how complicated it is to invent your own notation system and how much easier it would be if you had first a look on a site of rhythm, notation and basic triads.
May be after the latter effort you would be able to play every song you like and probably even this one:
enter image description here