How can I get other entity in script?

#1

Entity E1.
Script S.
S is the component In E1.
Here is another Entity E2.
How can I get E2 in S?
And if E1,E2 is not in the same Scene,how can I get it too?

#2

Got it in demo.
But it add a public Entity var in code then add it in XenkoStudio.Can I finish it just in Script file?