In general (but not exclusively), the datasources which Grafana offers the most benefits are time series databases, like Prometheus, InfluxDB, etc. as well as regular relational databases (MySQL, etc.). Grafana can also work with simpler datasources like .csv files or Google Sheets. Many of the panels / visualizations in Grafana expect there to be a “time” field, which is the basis for the complaining message that you observed.
Depending on your datasource, the “time” field will need to be named (or renamed) appropriately for Grafana to understand what is your time field.