Required Microsoft SharePoint Development,Microsoft SharePoint Administration freelancer for Reconnect Lookups Sharepoint Online Migration with Sharepoint Powershell job

I have an important but I assume common requirement. I am now using Sharepoint Online for data and documents. I have five excel tables that came from a previous project management software. The tables were once related but now are not because the lookups were disconnected.

When I import them into Sharepoint, the 4 lists (tables) have one lookup column that is linked to the one master list (table).

How do I re-create the relationship so that the lookup column is now active again, calling up the master list?

It seems like this would be a very common requirement for anyone migrating to Sharepoint, but cannot understand why there is almost no information on this.

At this point, it means that I would have to create a new lookup column linking to the master list, and manipulate each record one-by-one, to call up the particular item.

I see that there are tools like Sharegate, but they are way to expensive, and I assume that there has got to be a simple answer for a simple migration requirement.

At this point, when I create a new item in any of the 4 lists, I can do the lookup to the master list which is fine, but as I said, I would have to pick for each record.

I have found that Sharepoint Powershell can do this, but I need the simple script for this. I need a generic script with instructions, that I will use to correct the issue.

I thank everyone who responds to this, but I will not reply to those who have not done something similar before, nor can I respond to every request for more information.

Again, this is a common requirement that most people would have when moving from other programs via Excel to Sharepoint Online.

Remember, this is not for just importing, as that is easy. It is essentially creating a lookup column that no long exists, but matching the static data where the previous lookup column was.

Sorry, this is such a simple issue, but I don't know how to speak clearly about it, which it may come across something complicated, but I know enough about it that it is simple.

Skills & Expertise Required

Microsoft SharePoint Development Microsoft SharePoint Administration