It's quite the same as na-adjectives.
ような: attributive
熊のような犬
a dog like bear
ように: adverbial
風が台風のように強い。
The wind is strong like a typhoon.
ようだ: predicative(non-polite)
かなり高いようだ。
It seems to be rather high/expensive.
Note that "verb + ように" can mean "in order to/so that". See the following thread.
ように / 精一杯 questions | Japan Forum
I mean to change another form of negative なーadjective: ひまじゃありません。Yes for the negative but no for じゃある since ひまじゃある is invalid.
ひまではある is valid. は works as a contrastive marker here.
e.g.
今ひまではあるようです。(used when connoting でも、テレビを見たいようです or でも、気分が悪いようです, for instance)
Not only all na-adjectives but all negative forms including i-adjectives and verbs.This applies to all な adjective,Toritoribe san, am I right?
わかりました。Should be ひまではあるんです and ひまではあります。It's more likely both ひまじゃありません and ひまじゃないです change to ひまじゃない when attached to よう. ひまじゃありません and ひまじゃないです are both polite forms of ひまじゃない. The meanings are completely the same between these two forms. Only the level of politeness is different (ありません is more polite and formal than ないです).
ひまではあるです is invalid. What is the polite form of ある?
Not only all na-adjectives but all negative forms including i-adjectives and verbs.
ひまじゃありません/ひまじゃないです --> ひまじゃないようです
高くありません/高くないです --> 高くないようです
死にません/死なないです --> 死なないようです
This is getting complex. I thought both means there is no free time. Or should they mean "only exist when there is free time"? In what way are they different? I looked at Kim's grammar guide and still have no clue...ひまではあるんです is not a simple affirmative. It's different form ひまではあります in meaning/usage. See the following page.
Noun-related particles - Tae Kim's Japanese grammar guide
When the explanatory の/ん is applied to this structure, the form should be ひまではあるようなんです.
I am just a beginner. I guess ひまではあるんです and ひまではあります means "there is free time" butTae Kim explained about the explanatory の/ん very well. Almost all members who asked about it so far were satisfied with it.
You seem to be misunderstanding a very basic fact, by the way. ひまではあります is not a simple affirmative form of ひまじゃないです/ひまじゃありません, either. The polite affirmative form is ひまです.