Ok so I'll upload some pics and talk you through it if you like. Each pic should help to explain what I mean.
First step is to open up guts, select the "Scratch Pad" tab and add in all your UI elements (
Screenshot 1).
Right click on the white area on the left and add in a Logic Group (It has an icon to the left of it)
Underneath the Logic Group item is the "UI Menu" option. Mouseover then add a Menu Definition.
Then right click again and mouseover the "Logic" option. Add in a timer and Affix Applicator.
Now you've got your UI items you'll need to config their properties.
So..
Timer LOOP COUNT:1
LOOPS FOREVER:True
MAXTIME:-1
TIME:1
Affix Applicator (Affix in my screenshot)AFFIX: (type the name of your affix here)
APPLY ON PLAYERS: True
*Leave the rest as is*
Menu Definition (This is pretty important so I'll screenshot the properties)Main things to check are
ALWAYS VISIBLE: True
PINNED:True
MENU NAME: (Give it your own custom name)
*Double check everything else in
screenshot 2*
Now.. Last thing is to set up the Logic Group (
Screenshot 3). If you select the Logic Group you'll see that a hammer and wrench icon appears. Right click it and the Logic Editor will pop up. Now drag and drop the Timer and Affix from the left column into it.
In the Logic Editor, left click the Timer and check the "Activated" tickbox in its Outputs section.
Next left click the Affix Applicator and check the "Apply Affix" tickbox in its Inputs section.
(Every UI item has multiple things it can do in the Logic Editor. It's fun to dig around and see what they can do

Drag a line from the green square of "Activated" to the blue circle of "Apply Affix".
Now you've made it so that the affix you've selected will constantly apply the affix to players as long as the timer continues to loop, which it will do infinitely.
That should do it for you. One thing you can do to the affix while testing is to add a visual effect to it so you know if it's being applied properly. If you open up the affix you want to apply and type in "Poisoned" or "CHAMPIONGLOW" in the "UnitTheme" section for example, they will show up (as particle effects only) whenever the affix is active. A good way to check if it's working