Task Duration dependant on priorities

[BenRomeril]

Priority		Start	Finish	Duration (days)
1		=today()	+10 days	10
4				10
5				10
3				10
7				10

<tbody>
</tbody>

Populate Start / Finish columns based on Priority (including blank missing priorities)

 

[BenRomeril]

Priority		Start	Finish	Duration (days)
1		7/05/2019	17/05/2019	10
4		27/05/2019	6/06/2019	10
5		6/06/2019	16/06/2019	10
3		17/05/2019	27/05/2019	10
7		16/06/2019	26/06/2019	10

<tbody>
</tbody>

Formula to populate as completed here.
Thanks