Sorry for my response 3 month later. I don't know how new you are to this, but I would do the following:
1. In Excel, make sure that your X and Y columns are formatted to be numbers (not general).
2. In arcmap go to Tools> Add XY Data.
3. Click on the folder button and navigate to your excel spreadsheet. Select it.
4. In the field that says "X Field:" click on the drop down menu and select the name of the column from your excel spreadsheet that has your X values in it.
5. Repeat the same procedure for the "Y Field:" except select the column with your Y values.
6. Click the edit button below the box that says "Unknown Coordinate System" and navigate to the folder where the coordinate system is that you used to collect your XY data. When that is done, click ok to close the Add XY Data window.
7. You will be warned that you you can't perform certain functions with your data because it is a spreadsheet, don't worry about it, just click ok. Your data should appear as a line of points.
8. Create a shapefile from your data, to do this, in the table of contents, right-click on your layer>data>export data and navigate to where you want to save your shapefile. Name it, save it, display it in arcmap. Remove your XY data layer that references the spreadsheet.
9. Create a new Line shapefile.
10. Start an editing session, set your snapping so that as you draw your line, the cursor will snap to each point. Draw your line.
11. Save your edits in the edit session. Stop editing.
Hope this helps if not let me know if you have any other questions. I'll try to respond sooner next time.