There are several ways to do this. Here's one workflow:
1. Put the Lat Longs into an Excel spreadsheet.
2. Convert the Lat Longs to decimal degrees. Decimal Degrees = Degrees + (Minutes/60) + (Seconds/3600).
3. Add a new field and then number the Lat Long coordinate pairs in the sequence they need to be connected. For example, fieldname "SortOrder", then number each 1, 2, 3, etc in the order that they should be connected.
4. Follow this process (Add XY Data) to add the data to ArcGIS. This will create a point for each coordinate pair.
Adding x,y coordinate data as a layer—Help | ArcGIS for Desktop
5. The added data will be in what is called an Event layer in ArcGIS. Note that this is a temporary layer. Right-click and Data, Export Data to save off a permanent copy of the points.
6. Run the Points To Line geoprocessing tool on the point features, being sure to specify for the Sort Field (optional) the field name that has the order of the points so the lines are drawn in the correct order (which was created in step 3 above). For example, I called the field "SortOrder".
Points To Line—Help | ArcGIS for Desktop
Note - places where things go awry commonly happen at step 4, as formatting in Excel can be a culprit. If that happens, post here what went awry and we can troubleshoot it.
Also - an overview article of the same process:
Adding Excel Lat Long Coordinates into ArcGIS - GIS Geography
Chris Donohue, GISP
