Process chains doubt

Hi all,

How can we schedule and monitor the process chains.How can we know that the process chains are executed correctly and where can we get the error messages for the failed processes?

Also when i drag the attribute change run process after an execute infopackage process,inside the change run process there are different object types namely for infoobject,hierarchy and again execute inforpackage.some of the system suggested attribute change run process has the object type as execute infopackage.when should I use infoobject and when should i use execute infopackage for attribute change run process.Also when save hierarchy process is used,execute infopackage comes as default object type.should i have to change that to hierarchy object type.

Any suggestions is appreciated.

thanks.