Refresh M Query - Correct Syntax For Dates

I am exporting all data from a log table in App Insights to Power BI as an M query. I want to create a semantic model or dataflow in Power BI that allows me to refresh the data to retrieve the latest values from all columns in the table. I have been able to export the data and add it as a blank query in the advanced editor, but I am struggling with the correct way to use the timestamp field in the table to write in the date range in the M query.

Essentially, I'm hoping to (upon retrieval of new data) to have the query pull data from the last 90 days of data up to the current date/time. I am currently just getting the date range I set when querying the log data in App Insights before exporting the query. I only need the events and timestamps in the table to create some basic funnels, so I think defining the date correctly to get new data is the only hurdle.

For example, in SQL I would write it as: 

timestamp>=DATEADD(DAY,-90,CONVERT(date,GETDATE()))