Request a user certificate by following the instructions on the Dutchgrid Certification Authority website. A good starting point for finding your certificate authority if not available from this site is: https://www.eugridpma.org/members/worldmap/ (Europe) or http://www.igtf.net/ (World wide). Contact Science Data Centre Operations group if none of the above works.
Install the certificate by following the instructions provided by your certificate authority. Typically this involves:

Save the mail with the signed certificate as $HOME/.globus/usercert.pem and make sure that the userkey.pem file in that directory contains the pricate key that matches this certificate. As these *.pem files are strictly personal, their permissions should be set properly by the following command:
> chmod 600 *.pem
Load the certificate into your web browser. See e.g. http://ca.dutchgrid.nl/info/browser for instructions. Installation can also be done using the jGridstart tool (see above) for supported browsers.
Apply for authorization to use LOFAR resources:
- https://voms.grid.sara.nl:8443/voms/lofar for access to the LOFAR LTA storage.
NB If appropriate, you may be interested in applying for membership of other communities, e.g.:
- https://voms.grid.sara.nl:8443/vomses for other GRID communities hosted in the Netherlands.
- https://cic.gridops.org/index.php?section=home&page=volist for all Grid communities registered in Europe by discipline.

It's possible that on OSX Lion or Mountain Lion the jGridStart does not work. This is due to the java support for OSX moving from Apple to Oracle directly. To fix this check the following article http://support.apple.com/kb/HT5559 to get javaws on the commandline so you can use it like this: > javaws http://ca.dutchgrid.nl/start/jgridstart.jnlp . You can also download the latest java for OSX from Oracle and open /System/Library/CoreServices after that to update your CoreServices (you will just see a new Finder window, nothing seems to happen).
Sometimes the “install into browser” mode of the jGridStart doesn't work properly. In that case you can have jGridStart generate a .p12 file and import that into your browser manually. This seems openssl related as generating the .p12 with openssl on the commandline also seems to fail if this happens.

Installation of certificates