You have to make sure there are no empty entries. Fill them with the text 'NA'. Secondly make sure every label you have does not have any spaces in them. Example: if you have a column name like this 'UTM coordinate x' it will work fine in excel but not in the more precise R. You will need to change this to 'UTM.coordinate.x' or similar.
then copy paste your data field and then type this in R.
or save your datasheet as a .csv file and type:
or depending on if you are from the states or not:
mydataname=read.csv2(file.choose()) #this is when csv files are semicolon seperated.