With the current specifications, merge functions combine data into existing dataframes, so it would be better to create a new dataframe specifically for merging and then merge other data into it.
For creating data, you can use Text Input Data to manually create a dataframe.
https://exploratory.io/note/exploratory/How-to-Use-Text-Input-Data-klP6qIJ4
After that, please perform the merge process on the data you created above to combine everything into a single dataset.
https://exploratory.io/note/exploratory/How-to-Merge-Data-Frames-smR0hkM4