Where do I exclude data from input?

Hi, I'm sorry in advance for the really basic question but Splunk is all new to me and I couldn't find exactly what I want in the documentation. I have a server class (_server_app_PIA_App_Servers) that has an input to read logs from a specific application log directory (Peopletools Application Servers in this case). The logs have a lot of unimportant and repeating data and I don't want to index, mainly just things such as "checking for processes" that repeats every 5 seconds. I want to exclude this data from the index so it's not taking up unnecessary space and I'm pretty sure I need to add a props.conf and transforms.conf to do this (sending those lines to null with a transform) however I don't know WHERE to do it - do I put these in the Universal Forwarder /etc/apps/ directory for these specific servers, or do I put them on the Indexer in the DeployedApps directory and redeploy the app? Or somewhere else?? Thanks! Grahame