Automatic bar for project timeline

[HFGurgel13]

Hello everyone, I'm trying to make an Excel spreadsheet similar to MS Project. I need to fill column "E" with the lead time of the activity and indicate the predecessor activity in column "M". I need a formula that returns the Plan Start Week, taking into account the deadline of the predecessor activity.

For example, if activity 1.1 lasts for a week, activity 1.2 can only start in week 2.

[JeteMc]

The formula originally in cell N20 utilizes the XLOOKUP function which isn't supported by the 2013 version of Excel, if you are using the 365 version please update your profile.
That said I put the formulas in columns M:N which should work for the 2013 version.
M: =IFERROR(INDEX(A$6:A6,AGGREGATE(14,6,(ROW(A$6:A6)-ROW(A$5))/(D$6:D6=D20),1)),"")
N: =IFERROR(SUM(ROUND(INDEX(E$6:E6,AGGREGATE(14,6,(ROW(E$6:E6)-ROW(E$5))/(D$6:D6=D20),1))/7,0),INDEX(N$6:N6,AGGREGATE(14,6,(ROW(E$6:E6)-ROW(E$5))/(D$6:D6=D20),1))),1)
Let us know if you have any questions.