Liming soil

Anyone out there who could advise me on liming my soil. I know it sweetens it and my silty soil is about neutral pH and it will help create a better soil structure. I've never limed before and I'm not sure how long after liming I can add my rotted sheep manure. 

If your soil is about neutral, you don't need to lime it unless you want to grow chalk-lovers.  Most soil is on the acid side of neutral (pH 6-7), so that's what most plants are adapted to.  One possible exception is brassicas, because clubroot is much less successful at slightly alkaline pH.  However, if clubroot isn't a problem in your patch, and if you want to grow potatoes which need a slightly acid soil, don't do it!  The lightening texture thing is for heavy clays, and the sweetening is for soils that are very acid (ie acid enough that bacterial activity is dropping off like in a peat bog), so you don't need it for either reason.  If you overlime (or lime healthy soil like yours) you'll risk mineral deficiencies and certain diseases like potato scab, and you'll upset the soil fauna and bacteria that you want to encourage.